/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _ASM_HIGHMEM_H #define _ASM_HIGHMEM_H #include <asm/kmap_types.h> #define PKMAP_BASE (PAGE_OFFSET - PMD_SIZE) #define LAST_PKMAP PTRS_PER_PTE #define LAST_PKMAP_MASK (LAST_PKMAP - 1) #define PKMAP_NR(virt) (((virt) - PKMAP_BASE) >> PAGE_SHIFT) #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) #define flush_cache_kmaps() \ do { \ if (cache_is_vivt()) \ flush_cache_all(); \ } while (0) extern pte_t *pkmap_page_table; /* * The reason for kmap_high_get() is to ensure that the currently kmap'd * page usage count does not decrease to zero while we're using its * existing virtual mapping in an atomic context. With a VIVT cache this * is essential to do, but with a VIPT cache this is only an optimization * so not to pay the price of establishing a second mapping if an existing * one can be used. However, on platforms without hardware TLB maintenance * broadcast, we simply cannot use ARCH_NEEDS_KMAP_HIGH_GET at all since * the locking involved must also disable IRQs which is incompatible with * the IPI mechanism used by global TLB operations. */ #define ARCH_NEEDS_KMAP_HIGH_GET #if defined(CONFIG_SMP) && defined(CONFIG_CPU_TLB_V6) #undef ARCH_NEEDS_KMAP_HIGH_GET #if defined(CONFIG_HIGHMEM) && defined(CONFIG_CPU_CACHE_VIVT) #error "The sum of features in your kernel config cannot be supported together" #endif #endif /* * Needed to be able to broadcast the TLB invalidation for kmap. */ #ifdef CONFIG_ARM_ERRATA_798181 #undef ARCH_NEEDS_KMAP_HIGH_GET #endif #ifdef ARCH_NEEDS_KMAP_HIGH_GET extern void *kmap_high_get(struct page *page); #else static inline void *kmap_high_get(struct page *page) { return NULL; } #endif /* * The following functions are already defined by <linux/highmem.h> * when CONFIG_HIGHMEM is not set. */ #ifdef CONFIG_HIGHMEM extern void *kmap_atomic_pfn(unsigned long pfn); #endif #endif